New satellite control reaches commercialisation

A technology nurtured through ESA’s General Support Technology Programme (GSTP) has reached an important milestone, with Belgian company Veoware successfully commissioning its compact Control Moment Gyroscopes (CMGs) to fly on board a new, commercial satellite constellation.

CMGs have several benefits over traditional attitude control actuators; offering a higher torque output than reaction wheels (and thus faster maneuver time), and no fuel consumption compared to thrusters. Most CMGs contain high-speed flywheels spinning at up to 10 000 rpm with precision steering mechanisms that must operate reliably in the harsh environment of space for many years. This new ESA-supported CMG weighs just 4.2 kilograms, about the same as a vacuum cleaner, and is made up of two mechanisms inside a small box. Four of these boxes are usually mounted onto a spacecraft, each one able to move the spacecraft in one of three directions, with a fourth for redundancy and singularity avoidance.

“A control moment gyroscope looks simple from the outside, but in reality it combines extremely demanding mechanics, control algorithms and long-term reliability,” says ESA technical officer, Jeroen Vandersteen, who was in charge of the development from ESA’s side. “You have flywheels spinning at 10 000 rotations per minute for 7 or 8 years in the vacuum of space, while the precision gimbals continuously steer them in coordination to achieve exactly the right spacecraft motion. Getting all of that to work together is a significant engineering challenge.”

During in-orbit testing, Veoware’s mini CMGs enabled manoeuvres that were completed approximately 2.5 times faster than reaction wheels. An improvement that will help Earth observation satellites acquire more targets during each pass over the Earth.

All of this translates to a product that, at this size, is not widely available on the current European market. The achievement demonstrates how ESA’s technology programmes can help transform promising industrial concepts into commercially viable products.

“We are used to industry approaching us with initial ideas,” explains Jeroen. “In this instance, over a decade we were able to support this idea with a lot of technical advice and several iterating activities to create a miniature control moment gyroscope that can move the spacecraft and strengthen Europe’s autonomy in a key space technology.”

Supported through GSTP Element 2, the project is already part of follow-on activities to mature the hardware further. The next steps are to develop advanced control algorithms able to manoeuvre the two mechanisms and four mounted CMGs in synchronisation.

With few commercial suppliers worldwide and a product aimed at small to mid-sized satellites in the 50kg to 500kg range, the successful demonstration marks another example of how ESA-supported innovation is helping European companies bring strategic space technologies to market.